The Big 3 that enable you to join many affiliate programs and allow businesses
great exposure to many Web sites are:
* BeFree
* Commission Junction
* LinkShare
* Performics

These sites together offer over 1500 web sites with a diverse amount of products and services that can compliment your current Web site and allow your to earn more money.

Commission Junction has a diverse list of clients, some are nationally known others are smaller. Currently more than 230 affiliate programs.
Pros:
Earnings totals are COMBINED between ALL your affiliates at CJ
Check are sent out once $25.00 has been earned
Checks are mailed MONTHLY - rather than quarterly
New Feature Selected Stores - Individual items can be featured from merchants
Cons:
Some small company sites are terrible, newer affiliate are much better 
Link Options - vendors usually offer less than 10 link options
Reporting information is not very detailed

Linkshare also offers some big name sites, Disney.com, and many smaller
companies. They continue to add new and diverse affiliate programs.
Pros:
Can link to specific products via graphics and lead customers to the
order form
Cons:
Reporting information is not very strong
Merchants tend not to clearly identify their business and waste your time
Each merchant has a separate commission earning amount before payout

Befree represents some of the biggest names in online affiliate programs
including About, Barnes & Noble, Overture, and 800.com.
Pros:
Big name companies, you'll recognize the names
Merchants offer the most extensive banner and link options
Reporting is excellent and very informative
Cons:
You must meet each vendors earnings figure to get a check
Response to emails tends to be more than 5 days
Most programs send out checks Quarterly

So what about the Independents:
Amazon.com has the most affiliates of any online merchant and is very well run. However, many other programs have left plenty to be desired. Some never paid
out commissions or tracked sales properly, this resulted in scrutiny of many programs. Therefore we recommend you start with joining one of the "Big 3."

Our Favorites:
1. With a growing list of affiliate programs, a technology that is Web based, and a Commission that combines your earnings from ALL of your Affiliate Programs. Commission Junction - is our favorite. You get paid More Money, More Often and it's that simple.

Sign Up to Join Commission Junction Now!

Remember it is important to be paid for spending time promoting someone
else's business. Many of the programs set limits of $50 or $100 that a
small site with 1,000 - 5,000 pageviews may never reach in a year or
two. You may end selling $25 with one vendor, $35 with another, and $30
with another and never get a dime, but with Commission Junction you would
have receive $75 and you would only need to earn another $20 to get
another check.